Superluminescent or superradiant semiconductor diodes have a number of uses including fiber gyroscopes, and optical communications. Superluminescent diodes are characterized by very much higher power output than light emitting diodes, and by broad band radiation as compared with the narrow spectral frequencies of lasers. An exemplary superluminescent diode is essentially a one pass "laser" which emits at a large number of frequencies, rather than oscillating at certain preferred frequency modes.
It is desirable that a superluminescent diode (SLD) produce an output beam with low divergence and which can be easily coupled to an optical fiber. It is desirable to have high power output in either pulsed or CW modes of operation. For some applications it is desirable to have a high power SLD with wavelengths in the neighborhood of 0.7 to 0.9 microns as compared with the 1.3 to 1.5 micron wavelength ranges of the indium gallium arsenide phosphide family of semiconductors.
In the course of seeking a high power SLD in practice of this invention, it has been discovered that a much improved single mode, short wavelength, semiconductor laser can be provided. It is desirable to provide such a single mode laser where the side bands are largely suppressed.